package keypair;

//----------------------------------------------------------------------------
//$Id: GnuRSAPublicKey.java,v 1.3 2005/10/06 04:24:16 rsdio Exp $
//
//Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
//
//This file is part of GNU Crypto.
//
//GNU Crypto is free software; you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation; either version 2, or (at your option)
//any later version.
//
//GNU Crypto is distributed in the hope that it will be useful, but
//WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; see the file COPYING.  If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
//Linking this library statically or dynamically with other modules is
//making a combined work based on this library.  Thus, the terms and
//conditions of the GNU General Public License cover the whole
//combination.
//
//As a special exception, the copyright holders of this library give
//you permission to link this library with independent modules to
//produce an executable, regardless of the license terms of these
//independent modules, and to copy and distribute the resulting
//executable under terms of your choice, provided that you also meet,
//for each linked independent module, the terms and conditions of the
//license of that module.  An independent module is a module which is
//not derived from or based on this library.  If you modify this
//library, you may extend this exception to your version of the
//library, but you are not obligated to do so.  If you do not wish to
//do so, delete this exception statement from your version.
//----------------------------------------------------------------------------

import java.math.BigInteger;
import java.security.PublicKey;
import java.security.interfaces.RSAPublicKey;

/**
* <p>An object that encapsulates an RSA public key.</p>
*
* <p>References:</p>
* <ol>
*    <li><a href="http://www.cosic.esat.kuleuven.ac.be/nessie/workshop/submissions/rsa-pss.zip">
*    RSA-PSS Signature Scheme with Appendix, part B.</a><br>
*    Primitive specification and supporting documentation.<br>
*    Jakob Jonsson and Burt Kaliski.</li>
* </ol>
*
* @version $Revision: 1.3 $
*/
public class RsaPublicKey extends RsaKey implements PublicKey, RSAPublicKey {

private static final long serialVersionUID = -2504810529753771180L;

// Constants and variables
// -------------------------------------------------------------------------

/** The public exponent of an RSA public key. */
//private final BigInteger e;

// Constructor(s)
// -------------------------------------------------------------------------

/**
 * <p>Trivial constructor.</p>
 *
 * @param n the modulus.
 * @param e the public exponent.
 */
public RsaPublicKey(final BigInteger n, final BigInteger e) {
//   super(n);
   super(n, e);
//
//   this.e = e;
}

// Class methods
// -------------------------------------------------------------------------

/**
 * <p>A class method that takes the output of the <code>encodePublicKey()</code>
 * method of an RSA keypair codec object (an instance implementing
 * {@link IKeyPairCodec} for RSA keys, and re-constructs an
 * instance of this object.</p>
 *
 * @param k the contents of a previously encoded instance of this object.
 * @throws ArrayIndexOutOfBoundsException if there is not enough bytes, in
 * <code>k</code>, to represent a valid encoding of an instance of this object.
 * @throws IllegalArgumentException if the byte sequence does not represent a
 * valid encoding of an instance of this object.
 */
public static RsaPublicKey valueOf(final byte[] k) {
   // check magic...
   // we should parse here enough bytes to know which codec to use, and
   // direct the byte array to the appropriate codec.  since we only have one
   // codec, we could have immediately tried it; nevertheless since testing
   // one byte is cheaper than instatiating a codec that will fail we test
   // the first byte before we carry on.
   if (k[0] == Registry.MAGIC_RAW_RSA_PUBLIC_KEY[0]) {
      // it's likely to be in raw format. get a raw codec and hand it over
      final IKeyPairCodec codec = new RsaKeyPairRawCodec();
      return (RsaPublicKey) codec.decodePublicKey(k);
   } else {
      throw new IllegalArgumentException("magic");
   }
}

// Instance methods
// -------------------------------------------------------------------------

// java.security.interfaces.RSAPublicKey interface implementation ----------

//public BigInteger getPublicExponent() {
//   return e;
//}

// Other instance methods --------------------------------------------------

/**
 * <p>Returns the encoded form of this public key according to the designated
 * format.</p>
 *
 * @param format the desired format identifier of the resulting encoding.
 * @return the byte sequence encoding this key according to the designated
 * format.
 * @throws IllegalArgumentException if the format is not supported.
 * @see RsaKeyPairRawCodec
 */
@Override
public byte[] getEncoded(final int format) {
   final byte[] result;
   switch (format) {
   case IKeyPairCodec.RAW_FORMAT:
      result = new RsaKeyPairRawCodec().encodePublicKey(this);
      break;
   default:
      throw new IllegalArgumentException("format");
   }
   return result;
}

/**
 * <p>Returns <code>true</code> if the designated object is an instance of
 * this class and has the same RSA parameter values as this one.</p>
 *
 * @param obj the other non-null RSA key to compare to.
 * @return <code>true</code> if the designated object is of the same type and
 * value as this one.
 */
@Override
public boolean equals(final Object obj) {
   if (obj == null) {
      return false;
   }
   if (!(obj instanceof RSAPublicKey)) {
      return false;
   }
   final RSAPublicKey that = (RSAPublicKey) obj;
//   return super.equals(that) && e.equals(that.getPublicExponent());
   return super.equals(that)
         && getPublicExponent().equals(that.getPublicExponent());
}
}
